A servo control device includes an instruction controller that generates a motor motion instruction according to a program and a following controller that controls a motor according to the motor motion instruction, and it starts driving the motor using an external input signal as a trigger. For example, when the following controller detects the external input signal, the following controller notifies the instruction controller of a detection signal, and the instruction controller transmits the motor motion instruction to the following controller on the basis of the notification. Thus, a delay for communication time occurs from when the following controller detects the external input signal to when motor driving is started.
Patent Literature 1 describes that position instructions from start of positioning to completion of positioning, sent from a host controller that serves as an instruction controller, are saved in a servo driver that serves as a following controller in advance so that the servo driver can drive the motor independently from the host controller.